The present invention relates to devices for connecting working implements to tractors, and more particularly to a device for connecting a working implement to a tractor by three-point link system.
Three-point systems used for connecting a rotary tiller unit, plow or like working implement to the rear portion of tractors are designed to exhibit high working performance under hydraulic control.
When the three-point link system is used, there arises the necessity of connecting the implement to the tractor in tandem and also in offset position, because when the rotary tiller unit is connected to the tractor in offset arrangement, the outermost marginal area of the field can be completely treated. Thus it is desired to alter the arrangement of the working implement relative to the tractor in accordance with the working requirement.
Conventionally, a plurality of connector brackets are mounted on the front frame of the working implement at a specified spacing laterally thereof, and the three-point link system is connected at its rear end to the bracket selectively with use of hitch pins and hitch holes in the rear end of the system in order to render the working implement connectable to the tractor in either of tandem and offset positions interchangeably therebetween. However, since the connector brackets are secured to the front frame of the working implement, it is extremely difficult and troublesome to align the rear hitch holes of the three-point link system with the hitch pins. Moreover, the connection is not always smoothly operable free of troubles. Especially when the field is inclined and involves a difference in elevation in the transverse direction of the tractor and the implement, it is substantially impossible to adapt the connecting means for the situation. Furthermore when the working implement is arranged in offset position, the gauge wheels, which are subjected to the weight of the implement, should advantageously be shifted in conformity with the offset position, whereas the gauge wheels in the known structure are not shiftable and therefore not fully amenable to the operation of the tractor.